The present invention relates to methods and apparatus for processing voice over IP (VOIP) related messages within a broadband network, particularly a cable data network. More specifically, it relates to mechanisms for allowing a telephony service provider's network to be extended into a subscriber's home network providing voice over a packet switched network (e.g., the Internet).
Broadband access technologies such as cable, DSL, fiber optic, and wireless have seen a rapid adoption in recent years. Both the higher data rate and the ‘always on’ capability provided by broadband make it possible for an Internet service provider to deploy new applications/services. One of these applications is the traditional voice service offered by the public switched telephone network Recently, due in part to US deregulation of the telecommunications industry, ISPs (Internet Service Providers) have made great progress in deploying the hardware and software technologies required to support VOIP. Providing a telephony service over an IP infrastructure poses many challenges, not the least of which is the need to insure that the voice quality provided by this service is comparable with that of the PSTN (Public Switched Telephone Network). For networks that use a shared access medium to communicate between subscribers and the service provider (e.g., cable networks, wireless networks, etc.), the task of providing this reliable high-quality voice (and possibly video) communication is even more challenging. Further data networks are packet networks unlike the legacy PSTN telephony that is circuit switched. For a circuit switched network, there is fixed delay and ordered data transmission that leads to toll quality voice that is what one has today in the PSTN. A packet network has non linear delay, and audio packets get re ordered during transmission on the wire. Such properties of a packet network makes quality of service (QoS) a very important goal for VOIP telephony.
One type of broadband access technology relates to cable data networks. A cable network or “cable plant” employs cable modems, which are an improvement over conventional dialup PC data modems and provide virtually continuous, high speed connectivity. Cable modems are a good example of broadband customer access equipment that are instrumental in enhancing the broadband access network so that a service provider can deploy voice, video and data telecommunications services.
Currently (in the US) there are two main VOIP signaling protocols (NCS and SIP) that are being using by telephony service providers (TSP) in the deployment of their service. The customer premise device (e.g., residential gateway) speaks one of these signaling protocols in order to allow the user (usually via a ‘black phone’) to send and receive phone calls. However, the user may wish to use a different application/device than the one provided. Furthermore, this device may not implement the same signaling protocol as the one used by the TSP.
Unfortunately, since the components of the telephony service network, especially the user authentication and billing components that doles out QoS for the VOIP call, will be configured to implement the selected industry standard, users cannot currently use their alternative applications which use a non-standard protocol with their telephony service.
Accordingly, there is a need for mechanisms for allowing a VOIP user to utilize a communication protocol, such as SIP, that differs from the cable industry standard (e.g., NCS). Additionally, it would be desirable to provide the same voice quality to the user regardless of the device used to send or receive a particular phone call. Preferably, this is done without mandating the use of service RSVP (Resource Reservation Protocol) since this mechanism has not yet been widely adopted.